1. Field of the Invention
The present invention relates to a screwing and rolling head for the application of pre-threaded caps on containers with threaded necks.
2. Description of the Related Art
Pre-threaded caps for bottles have a cylindrical wall made of deformable metal material, for example, aluminium or the like, which is subjected to an operation of cold plastic deformation by means of rolling after screwing of the cap on the neck of the container. This rolling operation deforms an annular portion of the side wall of the cap against an annular groove provided on the neck of the container at the base of the thread.